The proposed research investigates the relationship between alcohol and different kinds of aggression in two rodent and one primate species. Three main objectives are pursued: (1) Analysis of pharmacological parameters and environmental determinants for alcohol's enhancing and depressant effects on attack and threat versus defense and flight in male and female animals; (2) Analysis of the possibly selective aggression-enhancing effects of alcohol, particularly in interaction with benzodiazepines, on aggression that is suppressed by aversive consequences; (3) Assessment of gonadal and adrenal hormones as possible mediators of alcohol's effects on aggresion in male and female animals. The behavioral research methodology relies on quantitative ethological analysis of species-specific aggressive, defensive and flight behavior. This approach will identify drug effects on animal behavior which is typical for a species and those which can be considered pathological patterns of behavior. The mehodology for reliably engendering stable patterns of attack, threat, defense, submission, flight and other agonistic and non-agonistic interactions focuses on confrontations between resident and intruder animals. Aggressive behavior will be decreased in frequency by using response-contingent presentation of aversive stimuli or, alternatively, by habituation procedures. Hormonal manipulations include castration and replacement with testosterone, adrenlaectomy and replacement with corticosterone and ACTH treatment. The study of alcohol effects on male and female aggression, their possible potentiation by benzodiazepines, and their possible mediation by hormonal mechanisms in several animal species is expected to provide a basis for prediction to humans.